The current electronic apparatuses for measuring amplitudes are expensive, call for the provision of supporting platforms for accelerometers, for their calibration, and impose certain requirements for operator's qualifications. Therefore, their employment under hard service conditions proves impractical. The measuring error of these apparatuses is .+-.10% (see, for example Catalogue of Schenck, Vibroport, FRG).
Known in the prior art is a method for measuring the vibration swings by an indicator-type lever-actuated mechanical instrument and recording the results on waxed paper, said instrument referred to as "vibrograph" (see, for example, "Instruments and Systems for Measuring Vibration, Noise and Impact". Reference Book vol. 2, Moscow, Machinostroyeniye 1978, p. 439). The use of such a vibrograph calls for providing supporting platforms on the vibration machine frame, said platforms being perpedicular to the main directions of vibrations.
Inaccuracies in the installation of supporting platforms, particularly in the case of elliptical vibration trajectories, a low-frequency component of vibrations of the machine and operator's hands as well as the error of the instrument proper, results in a large basic percentage error, reaching .+-.25%.
Most closely approaching the hereinproposed method is the known method comprising application of a sign in the form of a "measuring wedge" to the external surface of the vibration machine; during plane-parallel motion of the vibration machine said wedge forms a figure made by the extreme positions of the wedge due to the stroboscopic effect of visual perception (see, for example, Ju.N. Jorish "Vibrometry", Moscow 1963, p. 469). The vibration amplitude is determined by the point of intersections of the extreme wedge positions in accordance with the graduation scale.
The method of measurement with a measuring wedge is simple and fast, but its employment is restricted to measuring the rectilinear vibrations alone. Another substantial disadvantage is low measuring accuracy due to poor contrast (blurring) of the intersection point of contours arranged at an acute angle and to out-of-squareness of the wedge to the direction of vibration. This leads to a relative error of .+-.15% and impairs the adjustment of the vibration machine for an optimum operating mode.